FLAGSTAFF, Ariz. (AP) – Kaitlin Kenney was on a rafting trip through the Grand Canyon in January when she wrote a journal entry about her deep respect for the unforgiving environment and her desire not to become too intoxicated and keep a clear head.

For whatever reason, she let loose one day about halfway through the monthlong trip, drinking alcohol. She wandered away from her group as a fire was burning at the campsite and was never seen alive again. The body of the 21-year-old Englewood woman was found floating in the Colorado River two months later after an extensive search.

The details about the ill-fated trip were revealed in witness interviews and incident reports obtained by The Associated Press under a Freedom of Information Act request, and they demonstrate the dangers in consuming alcohol and drugs during camping and rafting trips in an area where help doesn’t arrive quickly because of the isolation.

“They had been in the river awhile and had no problems,” Grand Canyon National Park Chief Ranger Bill Wright said of Kenney’s group. “I think sometimes you get to that point where you think, ‘this can’t hurt me.’ You get a little lackadaisical because you had no problems. That’s where they forgot there’s still an inherent risk here.”

Rafting through the Grand Canyon is a big industry as thousands vie each year for coveted self-guided trips through a lottery system, and commercial guides offer excursions through the majestic canyon walls. Cracking open beers while floating down the river or sitting around a campfire often is part of the culture on the trips, but experts say people sometimes overlook the risks of partying as they enter into the wilderness.

“Just because you’re on a river trip or (in) a wilderness area, it doesn’t mean all the rules of society are suspended,” Wally Rist, president of the Grand Canyon Private Boaters Association. “That’s kind of the mindset that sometimes prevails with people on a river trip, is that everything goes because we’re out in the middle of nowhere.”

Rafters meet with a ranger before they launch so their equipment can be inspected. They also go through a 45-minute orientation that includes safety tips such as watching out for animals, what to do if someone falls into the water or the raft overturns. The tips don’t include anything specifically on drinking while rafting – anyone who is of legal age can do so.

Some groups minimize the risk of people falling into the river when they’re at camp by roping off the waterline, putting a life jacket on anyone who is drinking heavily and implementing a buddy system.

The National Park Service documents show that four days before she disappeared, Kenney wrote in her journal that “drinking out of control or to the point of unconsciousness is probably the most dangerous thing we can be doing out there.”

“There’s so many rocks, cacti, fire pans, cold water – this environment can be very, very unforgiving. … So on that note, I’m grateful I don’t like to get super drunk,” Kenney wrote.

Investigators asked Kenney’s fellow rafters why she might have strayed from her normal behavior of moderate consumption, but they got no explanation. Kenney wasn’t a big drinker, but “she might just have wanted to let loose,” her brother, Patrick Kenney, said Thursday.

The trip presented campers with many opportunities to do drugs and consume alcohol.

Members of Kenny’s group had beer, boxes of wine and shared whiskey with another group that visited their camp near Tapeats Creek. Other rafters have been known to pass around a bucket of hard liquor in the final days of their trip. Witnesses said Kenney brought mushrooms on the trip, and had eaten some in the days before she died.

Kenney was happy, dancing around a bit and smiling the last time anyone saw her. As the day wore on, her speech became incoherent and she was acting out of character, witnesses said. One man was put to bed early because he stumbled in to the river, soaking his clothing, according to the Park Service documents.

Kenney was up a half-hour earlier than everyone else the day she disappeared, walking upstream and playing her mandolin before she returned to the camp for breakfast. Later that day, the group hung around the fire and in smaller social circles. Eventually, they all peeled off to go to bed. No one realized Kenney didn’t make it into a tent until the next morning.

The group organized a search and found a single set of tracks about a quarter-mile downstream from the camp. It was one boot and one bare foot. The footprints ended altogether about a half-mile from the camp. Palm prints on rocks near the riverbank made the group think someone was using their hands for balance.

When they didn’t find Kenney, one of the rafters called the National Park Service from a satellite phone. Subsequent searches by helicopter and ground crews turned up no sign of her.

The autopsy report showed Kenney’s blood-alcohol content was 0.11 percent – higher than the state’s legal limit for driving of .08 percent. Testing of a liver sample turned up no traces of hallucinogenic mushrooms. Her body was pulled out of the river about 30 river miles from where she last was seen.

Patrick Kenney doesn’t believe there was any foul play in his sister’s death but thinks somebody may know something more about her disappearance.

“Maybe somebody had seen, gotten scared and didn’t know what to do and didn’t say anything,” he said.